In the field of packaging foods, there exist numerous and sophisticated packages for preserving flowable foods in an airtight state which are designed especially for transporting the food product from the manufacturer to the end user. However, these packages are generally useless for preserving the food products in the container after the package has been initially opened by the end user. This presents an economic loss to the end user since edible liquids and powders have a tendency to spoil as a result of exposure to oxygen, contamination from atmospheric impurities, exposure to bacteria or exposure to insects or other pests which infest the material, and/or exposure to light.
Some end user food preserving systems are known, such as reusable containers or resealable original packages. However, such known systems either trap a small quantity of air inside of the package during the sealing process or they improperly seal the food product, the result being that the contents remain subjected to the adverse effects of the above noted contaminants.
For example, U.S. Pat. No. 1,818,924 (Basmadjian) provides a cover for foodstuffs which floats on the surface of the foodstuffs. The cover of Basmadjian does not provide a seal for the container. It merely reduces the amount of air in contact with the surface of the foodstuffs and prevents the infestation of the foodstuff by insects such as flies.
U.S. Pat. No. 339,353 (Wiedemann) also provides a closure for a container which can be lowered into the container to reduce the airspace therein. The Wiedemann closure however, has two slots in it which allow air to circulate down into the food product.
Another example of a closure is shown in U.S. Pat. No. 2,605,009 (Landaal). This patent discloses a food guard which fits over the top of the food in a container to keep the food below the liquid level in the container. This food guard also allows air to circulate down into the container through the slots in the food guard.
Thus there exists a need for a new and improved, more efficient sealing device for sealing flowable foods such as liquids or powders for use by the customer, the end user, after or in the absence of manufacturer's airtight shipment container.